Switch-mode power-supply (SMPS) converters find use in a wide variety of applications, ranging from providing a fraction of a milliwatt of power in on-chip power management applications to providing hundreds of megawatts of power in municipal power systems. All of these applications require efficient and cost-effective static and dynamic power regulation over a wide range of operating conditions. An analog or digital controller closes the feedback loop around the switching converter and actively controls the on/off states of the power semiconductor devices to achieve input or output regulation.
For example, in FIG. 1, a power stage 105 of a power supply provides a voltage out. The voltage out is provided as a feedback signal to a comparator 110 that compares the voltage out to a reference signal and outputs an error signal. The error signal indicates how the voltage out differs from a target value indicated by the reference signal. An analog to digital converter 115 converts the error signal into a digital error signal processed by a digital compensator 120. The digital compensator 120 determines operating parameters for the power stage 105 based on the error and provides controlling signals to a digital pulse width modulator 125. The digital pulse width modulator 125 controls the operation of the power stage based on the controlling signals from the digital pulse width modulator 125.
Over the past few decades, digital controllers in the form of digital-signal processors (DSPs), microcontrollers, and field-programmable gate arrays (FPGAs) have grown in use in a variety of applications. Digital controllers rely on system or power supply design information to allow for accurate control of the power supply in response to feedback information from the power supply. Digital controllers, however, also introduce certain variables to the system including feedback quantization, control effort quantization, and delays for sampling the feedback information and calculating the control effort. To control these variables, power supplies and the digital controllers for the power supplies are typically modeled to allow designers to prepare operating parameters for each particular system.
In various applications, the digital controller should be tuned to achieve a desired dynamic performance including a fast dynamic response, minimum transients, and a stable closed-loop with a maximum bandwidth, minimum output impedance, and desired phase margin. Previous controllers, however, required user manipulation and input when creating mathematical models of the power supply, which impeded real time reactions to changing conditions for the power supply. For example, power-distribution systems containing multiple-power sources may experience dynamic performance degradation and even instabilities caused by uncertainties in the system parameters and interactions between different power modules.